Problem
1. How will you use find and perl to delete all ordinary files modified more than a year back? What is the advantage of using this method compared to using find with -exec rm?
2.
(i) Write a one-liner to change the she-bang line to #!/usr/local/bin/perl in all .pl files in the current directory.
(ii) Enlarge the scope to add the she-bang line if it doesn't exist. Also, don't attempt to make a substitution if a proper shebang line is already in place.